1. Field of the Invention
The present invention relates to extensometer devices for simultaneously measuring axial and torsional strain in the same specimen.
2. Description of the Prior Art
Various extensometers have been advanced in the prior art. An extensometer which uses a cross flexure mounting for two arm members engaging a specimen and which provides accurate measurements of strain is shown in U.S. Pat. No. 3,789,508. The cross flexure elements supporting the arms of the extensometer have strain gages mounted therein. The arms in turn have suitable knife edges or points which engage the specimen at two axially spaced locations and which are fastened to the specimen. When the specimen to which they are attached is loaded, the arms tend to separate, and the strain gages mounted on the flexure elements measure this strain accurately.
The device shown in U.S. Pat. No. 3,789,508 is designed to measure axial strains only, and not torsional strains.